Sulfonyl Azide Grafted Polyolefin Tie Layer
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Solution Overview
Problem
The existing free radical grafting process for producing maleic anhydride grafted polyolefin (MAH-g-PO) tie layers in multilayer films leads to undesired crosslinking and chain scission, affecting rheological properties and molecular weight, particularly when polypropylene is used.
Innovation Solution
A process involving the use of a sulfonyl azide derivative to graft a sulfonamide derivative onto olefin-based polymers, avoiding crosslinking and chain scission, and achieving high grafting efficiency, is employed to create a sulfonamide derivative grafted olefin-based polymer (SD-g-PO) tie layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If free radical grafting of maleic anhydride onto polyolefin is used to produce MAH-g-PO tie layer, then adhesion between polyolefin and polar substrate is improved, but crosslinking side reactions occur that deteriorate rheological properties (melt viscosity)
Solution Approach 1:
The patent changes the chemical parameters of the grafting process by using sulfonyl azide derivatives instead of free radical initiators, and employing extrusion processing conditions (temperature, shear rate) that favor grafting over crosslinking reactions, thereby achieving adhesion improvement without harmful crosslinking side reactions
Solution Approach 2:
The patent introduces sulfonyl azide derivative as an intermediary agent that facilitates the grafting of maleic anhydride to polyolefin through a controlled mechanism that avoids direct free radical crosslinking, serving as a mediating substance that enables adhesion while preventing harmful side reactions
2Strength
If free radical grafting is used to produce MAH-g-PO tie layer, then adhesion between polyolefin and polar substrate is improved, but chain scission side reactions occur that reduce molecular weight and increase melt flow rate
Solution Approach 1:
The patent modifies the reaction parameters by using sulfonyl azide initiation mechanism and controlling extrusion conditions to favor grafting reactions while suppressing chain scission, thereby maintaining molecular weight stability while achieving improved adhesion
Solution Approach 2:
The sulfonyl azide derivative acts as an intermediary that enables maleic anhydride grafting through a mechanism that does not involve aggressive free radicals capable of causing chain scission, thus preserving polymer molecular weight while achieving the desired adhesion enhancement
3Adaptability or versatility
If free radical grafting process is used, then MAH functionalization is achieved for tie layer application, but undesired crosslinking and chain scission affect the rheological properties of produced MAH-g-PO
Solution Approach 1:
The patent changes multiple parameters including the chemical nature of the initiator (sulfonyl azide vs. free radical), temperature profile, and shear conditions during extrusion to achieve MAH functionalization while suppressing harmful crosslinking and chain scission reactions, thereby improving rheological properties
Solution Approach 2:
The sulfonyl azide derivative serves as a controlled intermediary agent that enables MAH functionalization of polyolefin through a controlled reaction pathway that avoids the uncontrolled free radical reactions causing crosslinking and chain scission, thus achieving versatility without harmful side effects
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sulfonamide derivative grafted olefin-based polymer tie layer provides effective adhesion between dissimilar materials without the processing drawbacks of free-radical grafted MAH-g-PO, maintaining suitable adhesion properties for food and specialty packaging applications.
Implementation Method 1
melt blending a polyolefin and a sulfonyl azide derivative at a temperature greater than or equal to the decomposition temperature of the sulfonyl azide derivative
Implementation Method 2
The process includes the sulfonyl azide derivative to the polyolefin substrate with at least 50% grafting efficiency; and producing a sulfonamide derivative grafted polyolefin
Data Source
AI summary
The present disclosure provides a multilayer film. In an embodiment, a multilayer film is provided and includes: a layer (A) comprising an olefin-based polymer; a layer (B) that is a tie layer comprising a sulfonamide derivative grafted olefin-based polymer (SD-g-PO); and a layer (C) comprising a polar component.